<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script>
			//js中定义变量var，java非常严谨Sring，int，long
			var x =10;
			var y =20;
			console.log(x+y);
			var a=10;b=20;
			console.log(a*b);
			var x =100;//java中局部变量是不能重复定义
			console.log(x)//js语言常灵活，变量如果再次声明，就会被覆盖
			var x ="abc";//类型可以改变 Java中不行
			console.log(x);
			console.log(typeof(x));
		</script>
	</head>
	<body>
	</body>
</html>
